Geometry of the aortic bifurcation measured by computed tomography

Apart from metabolic risk factors haemodynamic disturbances play a role in atherogenesis. The haemodynamic factors depend among other things on the geometry of vessels including the aortic bifurcation. The geometry of the aortic bifurcation can be expressed by the diameter of the distal abdominal aorta, the area ratio of the bifurcation and the convergence of the aorta. Data on the geometry have been reported of both post-mortem and in-vivo investigations by angiography and echography. Because of the disadvantages of angiographic and echographic measurements, the aortic bifurcation has been assessed by CT-scanning in a series of 50 patients. The mean diameter of the distal aorta measured 15.9 mm for men and 13.0 mm for women. The calculated area ratio was 0.74 for men and 0.81 for women. These data are in agreement with the angiographic measurements. A convergence was found of 30.6 percent for men and 45.4 percent for women. There is a discrepancy between these values and those reported in the literature.